Room air conditioner with controls therefor



Dec. 27, 1966 A. H. KELLY 3,293,875

ROOM AIR CONDITIONER WITH CONTROLS THEREFOR Filed March 9, 1964 2 Sheets-Sheet 1 FIG].

WITNESSES INVENTOR Anthony H. Kelly ATTORNEY Dec. 27, 1966 A. H. KELLY ROOM AIR CONDITIONER WITH CONTROLS THEREFOR 2 SheetsSheet Filed March 9, 1964 United States Patent 3,293,875 ROOM AIR CONDITIONER WITH CONTROLS THEREFOR Anthony H. Kelly, Columbus, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 9, 1965, Ser. No. 438,269 6 Claims. (Cl. 62--180) This invention relates generally to room air conditioners, and in particular to a temperature control arrangement for room air conditioners.

An object of this invention is the provision of a structural arrangement which permits the safe and effective use of a bimetallic element for controlling an air conditioner in accordance with temperature variations of the room air.

The nature and substance of the invention, in brief, is the provision of an arrangement in which a minor portion of the room air handled bypasses the air conditioner evaporator and is directed across a bimetallic element located in a temperature control enclosure nested within a larger electrical components compartment. Further, the arrangement is such that straight-line penetration of the electrical components compartment is obstructed by the spatial relationship of the elements of the arrangement.

The invention will be described in connection with the accompanying drawing illustrating one embodiment of the invention incorporated in a room air conditioner by way of example, and wherein:

FIGURE 1 is a fragmentary isometric view of the room-side of one kind of room air conditioner in which the invention is advantageously incorporated;

FIG. 2 is a fragmentary, partly-broken, isometric view similar to FIG. 1, but with the front of the air conditioner removed.

FIG. 3 is a horizontal sectional view through a part of the room air conditioner, this view corresponding generally to one taken along the lines III-III of FIG. 2; and

FIG. 4 is a fragmentary, partly-broken, isometric view of the interior of the electrical components compartment as viewed from behind the temperature control enclosure and illustrating the relative disposition of some of the parts according to the invention.

The room side part of the air conditioner shown in FIG. 1 includes a box-shaped outer wrapper or housing having. a generally open room-side face covered by a louvered front 12. The lower part of the front includes a room air recirculation inlet 14 on the right through which the room air to be conditioned passes into the air conditioner, and a control face 16 on the left. The upper part 18 of the front serves as a discharge grill through which conditioned air is directed back into the room.

FIG. 2 shows the front 12 removed to expose the ele ments located behind the front. It may be seen that the upper and lower parts of the room-side face are divided by a horizontal shelf 20 extending between the opposite sides of the wrapper. The space immediately behind the recirculation inlet of the front contains an evaporator 22 of conventional character including vertical fins mounted on horizontally extending tubes. The left-side of the lower part is generally covered or blanked off by the cover 24. The upper or discharge part of the room-side face is generally unobstructed as shown.

The relationship of the different spaces of interest in the air conditioner is perhaps best perceived from FIG. 3 where the evaporator plenum 26 is shown on the right, and the electrical compartment 28 is shown on the left, with these two room-side spaces being separated from the outdoors-side space 30 by an upright bulkhead 32 which extends between the opposite sides of the outer partition has a slot 37 therein.

wrapper 10. The refrigerant compressor 34 is located in the outdoors-side space along with a condenser, condenser fan and fan motor (none of which are shown).

Considering again the room-side space of the air conditioner (i.e., the space in front of the bulkhead 32), separation of the space below the shelf 20 is provided by a vertical partition 36 between the evaporator plenum 26 and the electrical components compartment 28. The The evaporator 22 is supported in the plenum by a left bracket 38 having one or more openings 40 for the passage of bypass air. The room air fan 42 is located near the rear of the plenum and is arranged to draw air in through both the evaporator and the bypass passage (to be later described in detail), and force it out through the air outlet in the upper part of the front.

The electrical components compartment 28 is bounded on its opposite sides by the wrapper wall 10 and the vertical partition 36, at its rear by the bulkhead 32, and at its front by the control cover 24 provided with a recessed or dished central portion 44 (FIGS. 2 and 3). An escutcheon plate 46 is spaced forwardly of the cover 24 by means of upper and lower rearwardly-directed tabs 48 which serve as stand-offs so that a peripheral gap is formed between the plate and cover to permit the induction of the bypass air which then passes through slots 50 in the dished portion 44 of the cover.

A portion of the interior of the electrical components compartment 28 is partly isolated from the remainder by a box-shaped temperature control enclosure 52 secured against the rear face of the cover dished portion 44. The front face is provided with slots which register with the cover slots 50, and the right face of the enclosure is open. The currently preferred material for the enclosure is an insulating paper of relatively light gauge which is commonly termed fish paper. Except for the front and right faces of the temperature control enclosure, the walls are imperforate.

The enclosure 52 contains a temperature responsive control assembly generally designated 54 and mounted against the rear face of the cover 24. This assembly includes an electrical switch which controls compressor operation, and a bimetallic actuating element for operating the switch.

As shown in FIGS. 3 and 4, the bimetallic element 56 shown for purposes of example, is located behind switch 58, and these two elements along with a control shaft '60 are supported from the cover 24 by a bracket 61. The shaft projects forwardly through the cover and escutcheon plate 46 and carries atemperature control adjusting knob 62 on its outer end. The bimetallic element is disposed relative to the switch and upon a fulcrum 63 so that rotation of the shaft displaces the bimetallic element toward or away from the switch. A plunger 64 is provided to transmit the actuating force from the element to the switch. Electric wires 66 lead from the switch to the means for starting and stopping the refrigerant compressor.

The flow path of the bypass air is shown by the solid line arrows in FIGS. 3 and 4. It enters through the peripheral gap between the plate 46 and cover 24, passes through the inlet slots 50 into the enclosure 52, and flows past the bimetallic element 56 out the open right face of the enclosure and through the opening 37 in the vertical partition 36, opening 40 in the evaporator bracket and into the evaporator plenum. There the bypass air joins the main air stream which has been drawn through the evaporator. Consequently, the bypass air avoids the resistance imposed by the evaporator since it joins the main air stream downstream from the evaporator.

The relative locations and size of the openings for the bypass air are of significance in thesense that they help define the bypass air flow path and insure that the bimetallic element is enveloped by that air so that it will be responsive to room air temperature, Thus the inlets and outlet for the bypass air on generally opposite sides of the bimetallic element. The openings are also kept quite small to limit the amount of bypass air to a value which does not substantially reduce the capacity of the unit.

Also it will be appreciated that since the openings 37 in the vertical partition 36 performs a flow directing function, it should be of limited size. Of course it will be appreciated that other arrangements with respect to the relationship between the outlet of the temperature control enclosure and the opening through the vertical partition could be devised in light of the concept here disclosed.

The temperature control enclosure not only performs a flow directing function but in addition, coupled with the location of the bypass air inlets and outlets, performs a shielding function as well. The shielding function has two aspects. First, the bimetallic element 56 is thermally shielded from the surfaces of the electrical components compartment which are subject to ambient temperatures. Second, the air openings in the various members are arranged relative to the bimetallic element assembly to prevent straight-line penetration of any object into the electrical components compartment from the room side. This shielding against penetration is provided for purposes of safety since the electrical components compartment contains exposed electrical elements as represented in the drawing by the terminal block 68 and capacitor 70.

To summarize the operation of the room air conditioner as related to the subject matter of this invention, the desired room temperature is first set by adjusting control knob 62. This moves the bimetallic element 56 about its fulcrum 63 to a corresponding position relative to the associated switch 58-. With the air conditioner energized, if the room air temperature is sufficiently above the set point temperature, the passage of the bypass air past the bimetallic element heats the element and it responds by closing the switch to energize the compressor motor. The major part of the air is drawn through the evaporator 22 by the fan42, is cooled and discharged back into the room. When the room air temperature has been depressed sufficiently that the bimetallic element senses a temperature somewhat below the set point, the element moves away from the switch sufficiently that the switch opens and the compressor motor is stopped, However, the evaporator fan continues to draw air through both the evaporator and the bypass passage. Thus if the room air temperature again rises enough above the set point, the bimetallic element will respond and again energizes the compressor. Accordingly, the arrangement according to the invention provides for relatively close control of room air temperature.

The bimetallic and switch assembly, which in its currently preferred form is commercially identified as Norstat DR-15 available from the Norwalk Thermostat Company, provides distinct advantages as compared to the typical vapor or liquid filled control sensing bulb, and is arranged in a way which makes it rapidly responsive to variations in room temperature without any attendant sacrifice of electrical safety requirements.

I claim as my invention:

1. In a self-contained room air conditioner of the type adapted for window mounting:

an outer housing containing a bulkhead therein dividing said housing into a room-side space and an outdoorsside space;

an evaporator plenum in said room-side space containing a refrigerant evaporator at the face of said roomside space, and a room air fan in said room-side space for drawing room air through said evaporator and then forcing it back into the room;

an electrical components chamber in said room-side space adjacent said evaporator plenum but separated therefrom by a partition;

means defining a separate, temperature control space in said electrical components chamber;

a temperature responsive bimetallic element in said temperature control space for actuating electrical switch means controlling the operation of said air conditioner;

a front panel for said temperature control space including means defining an inlet opening in communication with the air in said room;

means defining an air outlet opening in said partition between said evaporator plenum and said temperature control space;

said bimetallic element being disposed generally in the path of air flow between said inlet opening and said air outlet opening to subject said bimetallic element to the temperature of the room air drawn through said temperature control space when said fan is operating.

2. In a room air conditioner as specified in claim 1:

said air outlet opening in said partition is located downstream of said evaporator so that said room air drawn through said temperature control space bypasses said evaporator.

3. In a self-contained room air conditioner of the type adapted for window mounting:

an outer housing containing a bulkhead therein dividing said housing into a room-side space and an outdoors-side space;

said room-side space presenting an open face to said room and being divided into an evaporator plenum containing an evaporator disposed in said open face and a room air recirculation fan downstream from said evaporator, and an adjacent, separate, electrical components chamber presenting an open-face to said room;

a generally vertical partition separating said evaporator plenum from said electrical components chamber, said partition including means defining in the air outlet opening therein;

cover means for said open-face of said electrical components compartment, said cover means including means defining an air inlet opening therein;

temperature control means mounted on said cover means and including a temperature responsive bimetallic element for actuating electrical switch means, said bimetallic element being disposed closely behind said cover means;

an enclosure mounted against the rear face of said cover means to encompass said air inlet opening and said bimetallic element, said enclosure including an open-face for air to leave said enclosure;

said air inlet opening and said air outlet opening in said partition means being disposed to define a path for the flow of room air through said temperature control space which passes over said bimetallic element and is admitted into said evaporator plenum downstream from said evaporator.

4. In an air conditioner according to claim 3:

said cover means includes a panel having slot means therein forming a downstream section of said air inlet opening, and a plate spaced forwardly from said panel to define peripheral gap areas along at least a part of the plate border to form an upstream section of said air inlet opening.

5. In an air conditioner according to claim 3:

said enclosure is disposed, relative to said air inlet opening, to substantially block straight-line penetration through said air inlet opening into said electrical components compartment.

6. In a self-contained room air conditioner of the type adapted for window mounting:

an outer housing;

a bulkhead in said outer casing dividing said housing into a room-side space, and an outdoors-side space;

an evaporator plenum in said room-side space containing a refrigerant evaporator located generally at the face of said room side-space, and a room air fan for drawing room air through said evaporator;

an electrical components chamber in said room-side space, said chamber being separated from said evaporator plenum by partition means;

means defining a separate, temperature control space in said electrical components chamber;

a unitary assembly including a temperature responsive bimetallic element and an electrical switch disposed to be actuated by movement of said element, said element being located in unshielded relation in said temperature control space and adapted to control operation of said air conditioner in accordance with variations in the temperature of air passing through said temperature control space;

cover means for the front of said temperature control space including means defining an air inlet opening placing said temperature control space in communication with room air;

means defining an outlet air flow path from said temperature control space to the space in said evaporator plenum between said evaporator and said room air fan so that room air leaving said temperature control space bypasses said evaporator;

said inlet opening and said air outlet path being disposed relative to said bimetallic element so that room air flows across said bimetallic element When said room air fan operates.

References Cited by the Examiner UNITED STATES PATENTS 1,770,765 7/1930 Bulkeley 165-20 X 3,185,393 5/1965 Norris 236-38 3,194,027 7/ 1965 Prendergast et a1 62-180 MEYER PERLIN, Primary Examiner.

ROBERT A. OLEARY, Examiner.

20 N. R. WILSON, Assistant Examiner. 

1. IN A SELF-CONTAINED ROOM AIR CONDITIONER OF THE TYPE ADAPTED FOR WINDOW MOUNTING: AN OUTER HOUSING CONTAINING A BULKHEAD THEREIN DIVIDING SAID HOUSING INTO A ROOM-SIDE SPACE AND AN OUTDOORSSIDE SPACE; AN EVAPORATOR PLENUM IN SAID ROOM-SIDE SPACE CONTAINING A REFRIGERANT EVAPORATOR AT THE FACE OF SAID ROOMSIDE SPACE, AND A ROOM AIR FAN IN SAID ROOM-SIDE SPACE FOR DRAWING ROOM AIR THROUGH SAID EVAPORATOR AND THEN FORCING IT BACK INTO THE ROOM; AN ELECTRICAL COMPONENTS CHAMBER IN SAID ROOM-SIDE SPACE ADJACENT SAID EVAPORATOR PLENUM BUT SEPARATED THEREFROM BY A PARTITION; MEANS DEFINING A SEPARATE, TEMPERATURE CONTROL SPACE IN SAID ELECTRICAL COMPONENTS CHAMBER; A TEMPERATURE RESPONSIVE BIMETALLIC ELEMENT IN SAID TEMPERATURE CONTROL SPACE FOR ACTUATING ELECTRICAL SWITCH MEANS CONTROLLING THE OPERATION OF SAID AIR CONDITIONER; A FRONT PANEL FOR SAID TEMPERATURE CONTROL SPACE INCLUDING MEAND DEFINING AN INLET OPENING IN COMMUNICATION WITH THE AIR IN SAID ROOM; MEANS DEFINING AN AIR OUTLET OPENING IN SAID PARTITION BETWEEN SAID EVAPORATOR PLENUM AND SAID TEMPERATURE CONTROL SPACE; SAID BIMETALLIC ELEMENT BEING DISPOSED GENERALLY IN THE PATH OF AIR FLOW BETWEEN SAID INLET OPENING AND SAID AIR OUTLET OPENING TO SUBJECT SAID BIMETALLIC ELEMENT TO THE TEMPERATURE OF THE ROOM AIR DRAWN THROUGH SAID TEMPERATURE CONTROL SPACE WHEN SAID FAN IS OPERATING. 